WO2011092958A1

WO2011092958A1 - Pump tappet

Info

Publication number: WO2011092958A1
Application number: PCT/JP2010/072466
Authority: WO
Inventors: 雅西村; 真司大石; 加藤　晃央
Original assignee: Ntn株式会社
Priority date: 2010-01-27
Filing date: 2010-12-14
Publication date: 2011-08-04
Also published as: EP2530295A4; US20120294741A1; EP2530295A1; JP5496696B2; CN102741540A; JP2011153573A; CN102741540B; EP2530295B1

Abstract

Provided is a pump tappet which can bear a large load of a pump plunger even when an intermediate base of a case which is a structural member of the pump tappet is made thin, and which has reduced weight of the entirety thereof. A case of a pump tappet is formed from an intermediate member (40) in which an intermediate base (40c) portion has continuous fiber flow. The case of the pump tappet is formed by means of a cold forging process in which both surfaces of a center part of a round steel bar material are pressed to extrude the body of the center part to the surrounding parts and the body of the round steel bar material is caused to flow vertically in the axial direction.

Description

Tappet for pump

This invention relates to a tappet for a pump.

In automobile direct injection engines, high-pressure fuel pumps are used to inject high-pressure fuel into cylinders. The high-pressure fuel pump converts the rotational motion of the camshaft provided with the cam to the reciprocating linear motion of the pump plunger, and feeds fuel by the reciprocating linear motion of the pump plunger to increase the pressure in the high-pressure chamber and into the combustion chamber. Fuel is supplied by injection. As a constituent member of the high-pressure fuel pump, there is a pump tappet that transmits the rotational motion of the camshaft to the pump plunger as a reciprocating linear motion.

There are several types of pump tappets, such as roller tappets with roller bearings and mushroom tappets, depending on the shape of the contact portion with the cam.

A technology related to a high-pressure pump provided with roller tappets is disclosed in DE 10 2005 047 234 A1 (Patent Document 1). FIG. 20 is a cross-sectional view showing a part of the high-pressure pump of Patent Document 1 that includes a roller tappet.

The high-pressure pump shown in Patent Document 1 is in contact with a camshaft 1 that rotates in the direction of arrow A in FIG. 20, a cam 2 provided on the outer diameter side of the camshaft, and the cam 2. The rotary motion of the camshaft 1 is transmitted as a reciprocating linear motion to a pump plunger 3 (hereinafter simply referred to as “plunger”), and the tappet 4 that performs the reciprocating linear motion and the reciprocating linear motion in contact with the tappet 4 are performed. The plunger 3 as a rod-shaped member, a high-pressure chamber (not shown) for sending fuel according to the reciprocating linear motion of the plunger 3 and increasing pressure, and the tappet 4 are in contact with each other, and the plunger 3 is arranged on the inner side. A spring 5 provided in this way, and a housing 6 that accommodates the tappet 4, the plunger 3, and the spring 5 are provided.

The tappet 4, the plunger 3 and the spring 5 are arranged so as to be accommodated in the opening hole 7 provided in the housing 6. The tappet 4 is guided by the inner diameter surface of the opening hole 7 in the vertical direction in FIG. 20, that is, in the direction of the arrow XX in FIG.

The camshaft 1 and the tappet 4 are arranged so that the outer diameter surface of the cam 2 and the outer diameter surface of the outer ring 8a of the roller bearing 8 accommodated in the tappet 4 come into contact with each other. One end portion 3 a of the plunger 3 is disposed so as to contact an intermediate bottom provided in the case 9 that is a constituent member of the tappet 4. The spring 5 is arranged so that one end thereof is in contact with a spring seat 10 provided on the lower side of the intermediate bottom.

The spring 5 has an elastic force in the downward direction, that is, the direction opposite to the direction indicated by the arrow XX in FIG. The tappet 4 is urged upward by the elastic force of the spring 5 via the plunger 3, that is, in the direction indicated by the arrow XX in FIG. 20.

The tappet 4 and the plunger 3 are moved in the vertical direction, that is, in the direction of the arrow XX in FIG. 20 or vice versa by the rotational movement of the camshaft 1, the urging of the spring 5, and the guide of the inner diameter surface of the opening hole 7. Make a reciprocating linear motion in the direction. The reciprocating linear motion here is a motion in the direction of arrow XX in FIG. 20 or in the opposite direction. The tappet 4 performs a reciprocating linear motion in the direction of arrow XX in FIG. 20 or the opposite direction. When the camshaft 1 rotates at a high speed, the speed of the reciprocating linear motion of the tappet 4 and the plunger 3 also increases.

The high pressure chamber is arranged on the other end side (not shown) of the plunger 3. The reciprocating linear motion of the plunger 3 can increase the pressure of the fuel supplied into the high pressure chamber.

By the way, it is expected that the load applied to the intermediate bottom of the tappet 4 that comes into contact with the plunger 3 of the pump will increase as the pressure of the fuel pump increases. However, if the load becomes high, the intermediate bottom may be damaged.
As a solution for this, as shown in Japanese Patent Laid-Open No. 01-110877 (Patent Document 2) and Japanese Translation of PCT International Publication No. 2001-500281 (Patent Document 3), the thickness of the pump plunger contact portion at the intermediate bottom is increased. A method is conceivable.

DE 10 2005 047 234 A1 Japanese Unexamined Patent Publication No. 01-110877 JP-T-2001-500221

However, when the wall thickness of the intermediate bottom of the tappet 4 with which the plunger 3 of the pump contacts is increased, the weight increases accordingly. For this reason, the inertial force when the tappet 4 reciprocates increases, and there is a possibility that the pump cannot be driven efficiently due to the occurrence of jumping.

Conventionally, the case 9 which is a constituent member of the tappet 4 is an intermediate bottom which partitions a vertical space inside a cylindrical peripheral wall 9a as shown in FIG. It is formed in a shape with 9b.

As shown by the thin line in the schematic diagram of FIG. 19, the metal structure of the round bar steel material that is the material of the case 9 is a fibrous structure in which many fibers are gathered. The flow is called fiber flow.

As described above, when the case 9 is formed by cutting round steel bars from both sides by cutting, the fiber flow of the steel material has a fiber flow in the thickness direction at the intermediate bottom 9b as shown by thin lines in FIG. It is cut into a uniform state. For this reason, when a large load of the plunger 3 is applied in the fiber flow direction, the portion of the intermediate bottom 9b is easily broken along the fiber flow direction.

Therefore, when the case 9 is formed by cutting, in order to improve the load resistance of the intermediate bottom 9b portion, conventionally, the intermediate bottom 9b portion has to be formed thick, and the weight of the case 9 is increased accordingly. There was a problem that became larger.

Therefore, the present invention provides a case that can withstand a large load of the plunger even if the thickness of the intermediate bottom is reduced as a case that is a constituent member of the tappet, thereby reducing the weight of the entire tappet. It is to be an issue.

In order to solve the above-described problems, a pump tappet according to the present invention transmits a rotary motion of a camshaft provided with a cam to a pump plunger as a reciprocating linear motion, and the reciprocating linear motion together with the pump plunger. A shaft, an outer ring disposed on the outer diameter side of the shaft and rotatably supported on the shaft, and a case housing the shaft and the outer ring, the case including a cylindrical peripheral wall And an intermediate bottom provided at an intermediate position on the inner diameter surface of the peripheral wall so as to partition the vertical space. The case is formed by cold forging in which the center portion of the round steel bar is pressed from both sides to extrude the center portion of the meat to the periphery and flow up and down in the axial direction, and the fiber flow in the middle bottom portion is continuous. It exists as a feature.

The outer ring may be provided on a shaft via a rolling element such as a roller, or the rolling element may be omitted and provided directly in a shaft shape.

The pump tappet according to the present invention has a large load resistance even if the wall thickness is reduced because the fiber flow in the middle bottom portion of the case is continuously present without being cut as described above. Thus, the weight of the entire case can be reduced. Thereby, since the inertial force when the tappet reciprocates can be reduced, the occurrence of jumping can be suppressed and the pump can be driven efficiently.

The load flow from the pump plunger is improved by cold forging so that the direction of the fiber flow continuously present in the intermediate bottom is 90 degrees with respect to the load direction from the pump plunger. Can be made.

In addition, since the middle bottom of the case is formed by pressing the center part of the round steel bar from both sides, the fiber flow density of the middle bottom is higher than other parts of the case, and the load resistance of the middle bottom Is more improved.

Further, the density of the fiber flow at the joint between the intermediate bottom of the case and the cylindrical peripheral wall, that is, the corner portion is higher than that of the other portions, and the load resistance of the intermediate bottom is further improved.

Further, by inclining the edge of the cylindrical peripheral wall of the case so as to be lowered inward, the height of the case outer diameter portion in the direction I in FIG. The case component can be further reduced in weight without reducing the contact area with the inner diameter surface 16a.

Further, the inner surface of the cylindrical peripheral wall of the case that contacts the width surface of the outer ring is ironed to improve the roughness of the contact surface with the width surface of the outer ring, and contact with the width surface of the outer ring. Heat generation and wear due to can be suppressed.

Also, it is preferable to process the center of gravity of the case so as to be provided in the cylindrical portion of the case away from the shaft fixing portion. As a result, when the outer surface of the case is centerless ground, the case 23 can be prevented from tilting toward the shaft fixing portion, and the posture of the case 23 can be stabilized, so that the outer surface of the case can be centerless ground. become.

In addition, the intermediate bottom of the case preferably has a middle-high shape at the plunger contact portion. By making the plunger contact portion into a medium-high shape, wear of the intermediate bottom can be suppressed.

Since the tappet for a pump according to the present invention uses a case in which the fiber flow of the middle bottom portion is continuously present, the thickness of the middle bottom is thinner than the case where the fiber flow of the middle bottom is cut by cutting. Even so, the load resistance can be ensured and the weight of the entire case can be reduced. Thereby, since the inertial force when the tappet reciprocates can be reduced, the occurrence of jumping can be suppressed and the pump can be driven efficiently.

It is sectional drawing which shows a part of high-pressure pump containing the tappet which concerns on one Embodiment of this invention. It is a vertical front view of the tappet contained in the high pressure pump shown in FIG. It is a vertical side view of the tappet contained in the high pressure pump shown in FIG. FIG. 4 is a perspective view of the tappet shown in FIGS. 2 and 3. It is the figure which looked at the tappet shown in FIG. 4 from the direction of arrow V in FIG. It is the figure which looked at the tappet shown in FIG. 4 from the direction of arrow VI in FIG. It is the figure which looked at the tappet shown in FIG. 4 from the direction of arrow VII in FIG. It is the figure which looked at the tappet shown in FIG. 4 from the direction of arrow VIII in FIG. It is an enlarged view of the part shown by IX of the tappet shown in FIG. It is the figure which looked at a part of roller bearing contained in the tappet shown in FIG. 2 from the direction of arrow X in FIG. FIG. 10 is a cross-sectional view of a part of the roller bearing included in the tappet shown in FIG. 2, which is a cross-sectional view cut along XI-XI in FIG. 9. It is a figure which shows the state which forms the intermediate material of the case contained in the tappet which concerns on embodiment of this invention by pressure processing. It is the schematic of the intermediate material of the case contained in the tappet which concerns on embodiment of this invention. It is a schematic diagram of the intermediate material of other embodiment of the case contained in the tappet concerning this invention. It is a vertical side view explaining the contact state of the intermediate bottom and plunger in embodiment of the case contained in the tappet concerning this invention. It is a vertical side view explaining the contact state of the intermediate bottom and plunger in other embodiment of the case contained in the tappet concerning this invention. It is a vertical front view which shows other embodiment of the tappet which concerns on this invention. It is a vertical side view which shows other embodiment of the tappet which concerns on this invention. It is a schematic diagram which shows the intermediate material of the case contained in the conventional tappet. It is sectional drawing which shows a part of high pressure pump containing the conventional tappet.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
A high pressure pump 11 including a tappet according to an embodiment of the present invention has a cam 12a provided on the outer diameter side thereof, a camshaft 12 that rotates in the direction of arrow A in FIG. The tappet 21 that abuts and transmits the rotary motion of the camshaft 12 as a reciprocating linear motion to the pump plunger 13 (hereinafter simply referred to as “plunger”) and performs the reciprocating linear motion, and the reciprocating linear motion abutting the tappet 21 Plunger 13 as a rod-shaped member that moves, a high-pressure chamber (not shown) that feeds fuel according to the reciprocating linear motion of plunger 13, abuts against tappet 21, and moves plunger 13 inward. A spring 14 provided so as to be disposed; and a housing 15 that accommodates the tappet 21, the plunger 13, and the spring 14. That.

The tappet 21, the plunger 13, and the spring 14 are arranged so as to be accommodated in the opening hole 16 provided in the housing 15. The tappet 21 is guided by the inner surface 16a of the opening hole 16 in the vertical direction in FIG. 1, that is, in the direction of the arrow I in FIG.

The camshaft 12 and the tappet 21 are arranged so that the outer diameter surface 12b of the cam 12a and the outer diameter surface 32a of the outer ring 32 of the roller bearing 31 included in the tappet 21 come into contact with each other. One end 13 a of the plunger 13 is disposed so as to abut on an intermediate bottom 23 c provided in a case 23 included in the tappet 21. The spring 14 is arranged so that one end thereof is in contact with a spring seat 17 provided on the lower side of the intermediate bottom 23c.

The spring 14 has an elastic force in the downward direction, that is, in the direction opposite to the direction indicated by the arrow I in FIG. The tappet 21 is urged upward by the elastic force of the spring 14 in the upward direction, that is, in the direction indicated by the arrow I in FIG.

The tappet 21 and the plunger 13 are moved in the vertical direction, that is, in the direction of the arrow I in FIG. Reciprocating linear motion in the direction of. The reciprocating linear motion here is a motion in the direction of arrow I in FIG. 1 or in the opposite direction. The tappet 21 reciprocates linearly in the direction of arrow I in FIG. When the camshaft 12 rotates at a high speed, the speed of the reciprocating linear motion of the tappet 21 and the plunger 13 also increases.

The high pressure chamber is disposed on the other end side (not shown) of the plunger 13. The reciprocating linear motion of the plunger 13 can increase the pressure of the fuel supplied to the high pressure chamber.

Next, the configuration of the tappet 21 according to an embodiment of the present invention will be described. The tappet 21 includes a shaft 22, a roller bearing 31 that is disposed on the outer diameter side of the shaft 22 and is rotatably supported on the shaft 22, and a case 23 that houses the shaft 22 and the roller bearing 31.

The case 23 includes a cylindrical peripheral wall 23a and an intermediate bottom 23c provided at an intermediate position on the inner diameter surface 23b of the peripheral wall 23a so as to partition the vertical space. Of the case 23, the intermediate bottom 23 c is in contact with the plunger 13. The peripheral wall 23a and the intermediate bottom 23c have a predetermined thickness.

As shown in FIG. 3, a pair of support holes 23 d and 23 e for supporting the shaft 22 are provided on one end side of the peripheral wall 23 a. The shaft 22 is arranged so that the shaft 22 is inserted into the pair of

support holes

23d and 23e. A roller bearing 31 is disposed on the outer diameter side of the shaft 22. Thus, the case 23 accommodates the shaft 22 and the roller bearing 31 in the space 23f from the intermediate bottom 23c toward the one end side of the peripheral wall 23a.

The shaft 22 is formed in a hollow shape, and is fixed to the support holes 23d and 23e by caulking and fixing the outer peripheral edge of the end surface of the shaft 22. Reference numeral 22a indicates a caulking portion. By making the shaft 22 hollow, the weight can be reduced as compared with the case of using a solid shaft.

A part of the plunger 13 is accommodated in the space 23g from the intermediate bottom 23c toward the other end of the peripheral wall 23a. Specifically, the one end portion 13a of the plunger 13 is disposed so as to contact the central portion in the radial direction of the intermediate bottom 23c, and the one end portion 13a of the plunger 13 is accommodated. Note that one end of the spring 14 is also accommodated in the space 23g.

The middle bottom 23c is provided with four oil holes 25 penetrating in the thickness direction (see FIGS. 7 and 8). The four oil holes 25 are provided so as to avoid a contact portion between the one end portion 13a of the plunger 13 and the intermediate bottom 23c. By using this oil hole 25, the lubricating oil supplied to the tappet 21 can be passed between the space 23f and the space 23g.

As shown in FIG. 2, the case 23 is provided with a through hole 23i as a recess that penetrates from the outer diameter surface 23h to the inner diameter surface 23b of the peripheral wall 23a. A locking pin 24 is fitted into the through hole 23i so that a part of the through hole 23i protrudes from the outer diameter surface 23h. The locking pin 24 positions the tappet 21 disposed in the opening hole 16. That is, the tappet 21 includes a rotation prevention pin 24 that positions the case 23.

The anti-rotation pin 24 includes a leg portion 24a fitted in the through hole 23i and a semi-spherical head portion 24b protruding from the outer diameter surface 23h. Here, the rotation prevention pin 24 is fixed by press-fitting the leg portion 24a into the through hole 23i, and prevents the drop from the through hole 23i.

A concave groove 16b extending in the direction of arrow I in FIG. 1 is provided on the inner diameter surface 16a of the opening hole 16 of the housing 15 so as to be recessed from the inner diameter surface 16a. When the tappet 21 is accommodated in the opening hole 16, the head portion 24b of the detent pin 24 is fitted into the concave groove 16b. Thereby, the case 23 in the opening hole 16, and the positioning of the tappet 21 in the circumferential direction is performed. Thereby, rotation to the circumferential direction of the tappet 21 in the opening hole 16 can be prevented.

Next, the configuration of the roller bearing 31 included in the tappet 21 will be described. FIG. 9 is an enlarged view of a portion indicated by IX of the two-dot chain line in FIG. A roller pitch circle 31a is indicated by a one-dot chain line in FIG. FIG. 10 is a view of a part of the roller bearing 31 seen from the direction of the arrow X shown in FIG. FIG. 11 is a cross-sectional view showing a part of the roller bearing 31, and is a XI-XI cross section in FIG. The roller bearing 31 includes an outer ring 32, a plurality of rollers 33 disposed between the outer ring 32 and the shaft 22, and a cage 34 that holds the plurality of rollers 33.

The retainer 34 includes a pair of

annular portions

34a and 34b and a plurality of column portions 34d that connect the pair of

annular portions

34a and 34b so as to form a pocket 34c that accommodates the rollers 33. The column portion 34d has a shape that extends straight in the axial direction, that is, in the cross section shown in FIG.

The retainer 34 is disposed between the outer ring 32 and the shaft 22 similarly to the rollers 33. The plurality of rollers 33 are accommodated and held in the respective pockets 34 c provided in the cage 34. The retainer 34 is configured such that the outer diameter guide, that is, the inner diameter surface 32 b of the outer ring 32 disposed on the outer diameter side of the retainer 34 and the outer diameter surface 34 e of the retainer 34 are in radial contact. Further, the retainer 34 is provided with an oil groove 34f so as to be recessed inward from the outer diameter surface 34e. The oil groove 34f is provided at the center of the column portion 34d and has a shape extending in the circumferential direction.

Rotational motion of the camshaft 12 also rotates the outer ring 32 and the rollers 33 that are constituent members of the roller bearing 31. When the camshaft 12 rotates at a high speed, the rotation of the rollers 33 also increases. Here, in the roller bearing 31 which is a constituent member of the tappet 21, the position of the roller 33 in the roller bearing 31 at the time of high speed rotation can be stabilized by the cage 34. Then, the skew of the roller 33 can be suppressed and the lateral running of the roller bearing 31 can be prevented. Accordingly, it is possible to reduce the risk of poor lubrication of the roller bearing 31 and wear of the roller bearing 31 during high-speed rotation. That is, such a pump tappet can be manufactured at a low cost and can have a long life.

Further, such a high-pressure pump 11 includes a tappet 21 that can be manufactured at a low cost and can reduce the risk of poor lubrication of the roller bearing 31 and wear of the roller bearing 31 during high-speed rotation. The fuel can be manufactured at a low cost, and the pressure of the fuel can be increased more stably in a short time.

Here, the retainer 34 is an outer diameter guide, and the retainer 34 and the outer ring 32 are provided on the outer diameter surface 34e of the retainer 34 because an oil groove 34f that is recessed inward from the surface is provided. And the radial position of the cage 34 can be stabilized. Further, the oil permeability of the inner diameter surface 34g of the cage 34 and the outer diameter surface 22a of the shaft 22 is improved, and the lubricity between the outer diameter surface 34e of the cage 34 and the inner diameter surface 32b of the outer ring 32 is improved and retained. Wear of the vessel 34 and the outer ring 32 can be suppressed. Therefore, the life of the cage 34, the rollers 33, the outer ring 32, and the shaft 22 can be extended. The oil groove may be provided so as to extend with an inclination in the axial direction, or may be provided so as to extend in a curved manner. A plurality of oil grooves may be provided.

Note that the cage 34 is an inner diameter guide, and an oil groove may be provided on the inner diameter surface 34 g of the cage 34. By carrying out like this, the holder | retainer 34 and the shaft 22 can be made to contact and the radial position of the holder | retainer 34 can be stabilized. Further, the oil permeability of the outer diameter surface 34e of the cage 34 and the inner diameter surface 32b of the outer ring 32 is improved, and the lubricity between the inner diameter surface 34g of the cage 34 and the outer diameter surface 22a of the shaft 22 is improved and retained. Wear of the vessel 34 and the shaft 22 can be suppressed. Therefore, the life of the cage 34, the rollers 33, the outer ring 32, and the shaft 22 can be extended.

The cage 34 provided in the roller bearing 31 may be made of resin. By carrying out like this, the holder | retainer 34 itself can be made lightweight and the weight of the tappet 21 can be lightened generally. Therefore, the force required for the reciprocating linear motion, here, the force required for the vertical movement of the tappet 21 can be reduced. Further, when the cage 34 is made of resin, it can be manufactured by injection molding or the like, so that mass production is facilitated and it can be manufactured at low cost. Examples of the material of the cage 34 include nylon 66, nylon 46, polyphenylene sulfide (PPS), polyether ether ketone (PEEK), and the like. If necessary, the resin may be filled with carbon fiber, glass fiber, carbon black, or the like.

In FIG. 10, the gap between the rolling surface 33a of the roller 33 accommodated in the pocket 34c and the side wall surface 34h of the column portion 34d is exaggerated and greatly illustrated from the viewpoint of facilitating understanding. Yes.

The rollers and shafts constituting the above-described tappet are manufactured by forging, cutting, or the like of a steel member such as SUJ2 or SCM420 (both JIS standards).

Here, in the above-described embodiment, the recess for fitting the rotation prevention pin is a through-hole penetrating from the inner diameter surface to the outer diameter surface of the case. It does not need to penetrate from the inner diameter surface to the outer diameter surface. Furthermore, you may comprise a recessed part so that it may have a shape dented from the outer diameter surface of the case so that the outer diameter surface of a rotation prevention pin may be met. By doing so, the outer diameter surface of the locking pin and the concave portion of the case are matched, and the locking pin and the concave portion can be more reliably fitted.

In the above-described embodiment, the cage includes a pair of annular portions and a plurality of pillar portions, but is not limited thereto, and is divided into a plurality of members instead of an integrated type, A spacer-type cage disposed between the rollers may be used.

Moreover, in the said embodiment, although the pillar part was made into the shape extended straightly to an axial direction, it is not restricted to this, For example, the pillar part may be bent by radial direction, for example, a V-type holder, It may be shaped like an M-type cage. Furthermore, it is good also as providing the roller stop part which prevents the fall-off | omission of the roller of the radial direction on the side wall surface of a pillar part.

In the above-described embodiment, the roller bearing is configured to include a cage that holds a plurality of rollers. However, the configuration is not limited thereto, that is, a configuration in which the roller bearing does not include a cage, that is, a full-roller type. The same applies to roller bearings.

The above embodiment is the tappet 21 in which the roller bearing 31 is provided on the outer diameter side of the shaft 22, but the embodiment shown in FIGS. 17 and 18 omits the rolling elements and the outer ring on the outer diameter side of the shaft 22. It is an example of the tappet 21 directly provided 32a so that rotation is possible, the part which is common in the said embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.

Next, the case 23 which is a constituent member of the tappet 21 according to the present invention will be described. As described above, the case 23 includes the cylindrical peripheral wall 23a and the intermediate bottom 23c provided in the middle of the inner diameter surface 23b of the peripheral wall 23a so as to partition the vertical space.

As shown in FIG. 19, the case 23 is conventionally formed by cutting a round bar steel material by cutting, and the fiber flow of the steel material is indicated by a thin line in the schematic schematic diagram of FIG. 19. The part was cut into a state where the fiber flow was aligned in the thickness direction. For this reason, when a large load of the plunger is applied in the direction of the fiber flow, there is a problem that the portion of the intermediate bottom easily breaks along the direction of the fiber flow.

In order to solve such a problem, in the present invention, as shown in FIG. 12, the intermediate material 40 of the case 23 is formed from a round bar steel material by cold forging. The intermediate material 40 includes a peripheral wall 40a that forms the cylindrical peripheral wall 23a of the case 23, and an intermediate bottom 40c that is provided at an intermediate position on the inner diameter surface 40b of the peripheral wall 40a so as to partition the vertical space of the peripheral wall 40a. The intermediate bottom 40 c forms the intermediate bottom 23 c of the case 23.
As shown in FIG. 12, the intermediate material 40 presses the center part of the round bar steel material in the die 41 with the upper punch 42 and the lower punch 43 to extrude the meat in the center part to the surroundings. An intermediate bottom 40c and a cylindrical peripheral wall 40a are formed by flowing vertically in the axial direction.

As shown in FIG. 13, the intermediate material 40 of the case 23 formed in this way has a continuous fiber flow between the intermediate bottom 40c and the peripheral wall 40a.

In the case 23 formed from the intermediate material 40, the fiber flow at the intermediate bottom 23c is continuously present without being cut. Therefore, even if the thickness of the intermediate bottom 23c is reduced, the weight of the entire case 23 can be reduced because it has a large load resistance. Thereby, since the inertial force when the tappet 21 reciprocates can be reduced, the occurrence of jumping can be suppressed and the pump can be driven efficiently.

The direction of the fiber flow continuously existing in the intermediate bottom 23c of the case 23 formed from the intermediate material 40 is cold forged so as to be in the direction of 90 degrees with respect to the load direction from the plunger 13, The load resistance from the plunger 13 is further improved.

Further, since the intermediate bottom 23c of the case 23 formed by cold forging as described above is formed by pressing the central portion of the round bar steel material from both sides, the fiber flow density of the intermediate bottom 23c is different from that of the case 23. The load resistance of the intermediate bottom 23c is further improved.

Further, when the case 23 is formed by cold forging as described above, the density of the fiber flow at the corner portion of the joint portion between the intermediate bottom 23c portion and the cylindrical peripheral wall 23b is also higher than other portions, The load resistance of the bottom 23c is further improved.

Further, when the intermediate material 40 of the case 23 is formed by cold forging, as shown in FIG. 14, the upper edge of the cylindrical peripheral wall 40a of the intermediate material 40 is formed into an inclined surface 40d that is lowered inward. Accordingly, the intermediate material of the case 23 is further reduced in weight without changing the height of the case outer diameter portion in the I direction in FIG. 1 and without reducing the contact area between the case outer diameter portion and the inner diameter surface 16a of the opening hole 16. 40 can be formed.

When forming the case 23 from the intermediate material 40, in order to improve the roughness of the contact surface with the width surface of the outer ring 32 of the rolling bearing 31, the space 23f of the case 23 that accommodates the shaft 22 and the roller bearing 31 is provided. It is desirable to iron the inner diameter surface 23b. By improving the roughness of the contact surface, it is possible to suppress heat generation and wear when contacting the width surface of the outer ring.

Further, when the intermediate material 40 forming the case 23 is processed, it is preferable to process the intermediate material 40 so that the center of gravity is provided on the cylindrical peripheral wall 40a away from the shaft fixing portion of the rolling bearing 31. As a result, when the outer surface of the intermediate material 40 is subjected to centerless grinding, the case 23 can be prevented from inclining toward the shaft fixing portion, and the posture of the case 23 can be stabilized. It becomes possible to process.

Next, the embodiment shown in FIG. 15 is an example in which the intermediate bottom 23c of the case 23 that contacts the one end 13a of the plunger 13 is a flat surface. Thus, when the intermediate bottom 23c of the case 23 is made flat, as shown in FIG. 15, when the plunger 13 is in contact with the intermediate bottom 23c of the case 23 in a tilted state due to the influence of mounting error or gap, Since one end 13a of the plunger 13 hits the middle bottom 23c of the case 23, the middle bottom 23c of the case 23 is easily worn. For this reason, in the embodiment shown in FIG. 16, the intermediate bottom 23 c of the case 23 that comes into contact with the one end 13 a of the plunger 13 is formed in a middle-high shape. In this way, by forming the intermediate bottom 23c of the case 23 in a medium-high shape, even when the plunger 13 is inclined, the contact between the plunger 13 and the intermediate bottom 23c does not come around the corner. Wear of the intermediate bottom 23c due to contact with the portion 13a can be suppressed.

As mentioned above, although embodiment of this invention was described with reference to drawings, this invention is not limited to the thing of embodiment shown in figure. Various modifications and variations can be made to the illustrated embodiment within the same range or equivalent range as the present invention.

The tappet according to the present invention is included in a high-pressure pump that supplies fuel to an engine of an automobile or the like, and is effectively used as an automobile part.

DESCRIPTION OF SYMBOLS 11 High pressure pump 12 Cam shaft 12a Cam 13 Plunger 13a One end 21 Tappet 22 Shaft 23 Case 23a Perimeter wall 23c Intermediate bottom 31

Roller bearing

32, 32a Outer ring 33 Roller 40 Intermediate material 40a Perimeter wall 40c Intermediate bottom

Claims

A pump tappet that transmits the rotational motion of a camshaft provided with a cam to a pump plunger as a reciprocating linear motion, and performs a reciprocating linear motion together with the pump plunger,
A shaft, an outer ring disposed on the outer diameter side of the shaft and rotatably supported on the shaft, and a case for housing the shaft and the outer ring,
The case includes a cylindrical peripheral wall and an intermediate bottom provided at an intermediate position on the inner diameter surface of the peripheral wall so as to partition the space in the vertical direction.
The case is formed by cold forging in which the central part of the round steel bar is pressed from both sides and the meat in the central part is pushed to the surroundings to flow up and down in the axial direction, and the fiber flow in the middle bottom part continues. Pump tappet characterized by the existence.
The pump tappet according to claim 1, wherein the outer ring is provided on a shaft via a rolling element.
The pump tappet according to claim 1 or 2, wherein the direction of the fiber flow continuously present on the intermediate bottom is 90 degrees with respect to the load direction from the pump plunger.
The pump tappet according to any one of claims 1 to 3, wherein the density of the fiber flow in the intermediate bottom is higher than that of other parts of the case.
The pump tappet according to any one of claims 1 to 4, wherein the density of fiber flow at the joint between the intermediate bottom and the cylindrical peripheral wall is higher than that of other parts of the case.
The pump tappet according to any one of claims 1 to 5, wherein an edge of the cylindrical peripheral wall has an inclined surface that is lowered inward.
The pump tappet according to any one of claims 1 to 6, wherein an inner diameter surface of a cylindrical peripheral wall of the case with which a width surface of the outer ring contacts is ironed.
The pump tappet according to any one of claims 1 to 7, wherein the center of gravity of the case is other than the shaft fixing portion.
The pump tappet according to any one of claims 1 to 8, wherein a pump plunger contact surface on an intermediate bottom of the case is formed in a medium-high shape.
A high pressure fuel pump using the pump tappet according to any one of claims 1 to 9.
An automobile or a motorcycle using the high-pressure fuel pump according to claim 10.